This invention relates in general to vehicular brake systems, and in particular is concerned with a control valve mounted in a hydraulic control unit of an electronically controlled brake system.
Electronically-controlled brake systems for vehicles are well known. One type of electronically-controlled brake system includes a hydraulic control unit (HCU) connected in fluid communication between a master cylinder and a plurality of wheel brakes. The HCU includes a housing containing control valves and other components for selectively controlling hydraulic brake pressure at the wheel brakes.
Control valves for HCU""s are commonly formed as electronically actuated solenoid valves. A typical solenoid valve includes a cylindrical armature slidably received in a sleeve or flux tube for movement relative to a valve seat. A spring is used to bias the armature in an open or closed position, thereby permitting or blocking fluid flow through the valve, respectively. A coil assembly is provided about the sleeve. When the valve is energized, an electromagnetic field or flux generated by the coil assembly slides the armature from the biased open or closed position to a closed or open position, respectively.
Control valves mounted in a HCU are actuated by an electronic control module to provide desired braking functions such as anti-lock braking, traction control, and vehicle stability control.
To provide desired braking responses, an armature must respond quickly and in a predictable manner to an electromagnetic field generated by an energized coil assembly.
This invention relates to a control valve mounted in a hydraulic control unit of a vehicular brake system. The control valve includes an overmolded armature slidably received in a sleeve. The armature reciprocates in the sleeve quickly and in a predictable manner when a coil assembly is energized.
In a preferred embodiment, a control valve for controlling fluid flow in a hydraulic control unit of a vehicular brake system includes a valve seat. A sleeve is mounted on the valve seat. An armature core is slidably received in the sleeve. The armature core has a passage extending between first and second planar end surfaces of the armature core. An armature body is formed from a moldable material onto the armature core. The armature body has a central section received in the passage of the armature core, a first end section extending from the first end surface of the armature core, and a second end section extending from the second end surface of the armature core.
This control valve is particularly adapted to be mounted in a bore of a housing of a hydraulic control unit of an electronically controlled vehicular brake system.